Talk:Instant-runoff voting

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Create a better lead section Get some good pictures Make sure NPOV Add references

Previous talk: /archive1

Contents 1 Misc 2 Changes to Example 3 Removed stuff on STV in Canada 3.1 BC-STV Referendum 3.2 Post-Referendum Debate and Aftermath 3.3 Electoral Reform in Other Provinces 4 What now? 5 More changes to examples 6 More NPOVing 7 Singular they 8 Corporate Governance & Civil Society 9 elimination in IRV 10 blog references? 11 Practical implications 11.1 strike approval plug 12 undocumented paragraph removed here 13 Removed text restored here 14 Similar systems 14.1 Runoff-voting 14.2 Contingent vote 15 Tactical voting and strategic nomination 16 Effect on parties and candidates 17 Condorcet vs. IRV 18 Problems 19 Tie breaking rule 20 This page is now protected 20.1 Discussion

[edit] Misc

FD:

Why isn't there a comparison between IRV and FPTP. Surely that is a more valuable comparison?

Thanks for adding the 'truncated' explanation. That makes more sense.

Contrary to the opening sentence, IRV can also be used for multi-member electorates - changed to normally.

That stuff about historical use in BC should be removed. It makes no sense to non-Canadians. This article is about a vote counting method, not Canadian politics.

Sorry I didn't realise this page was here before. I have removed the 'return of the third party spoiler effect' section because it made no sense. I think there is no spoiler effect - where people think there is it is actually failure to compromise. The difference between the two is that with failure to compromise, the candidate that gets unfairly eliminated has fewer primary votes than two other candidates, whereas for the spoiler effect the second candidate based on first rpeferences is unfairly eliminated because of a weaker candidate.

I like the Tenessee example because it is consistent through all the pages on voting systems.

We need to point out explicitly that all the 'relevant' criticisms of IRV also apply to first past the post as it reads like IRV might be worse than first past the post. They only make it 'worse' than condorcet methods.

What is NPOV?

re: condorcet vs IRV, the only advantage of condorcet is that it eliminates failure to compromise. However this never happens in real elections because IRV tends to drive the two major parties toward the political middle gorund anyway. Thus, condorcet methods give you added complexity (the vote counting would be horrendous and would probably need computerised voting) with no real benefit.

end FD

It is disingenuous to say that Condorcet provides "no real benefit" -- failing the participation criterion (which says, basically, that your own vote shouldn't hurt you) is seen by many people as a pretty big deal. Some cases in which IRV would tend to suffer from the Center Squeeze effect are quite plausible. See the French Presidential election of 2002, for example. I'm not sure how to format Wikipedia tables, but I'd be happy to write in a few examples in text. Additionally, Condorcet saves tremendously on the complexity of aggregating ballot information from polling stations into a central counting location. IRV ballots either must be transmitted with full ranking information (complexity of N-factorial), or must be counted and recounted, at the polling stations, as individual candidates are eliminated. Condorcet can be transmitted once, using the number of points to each candidate in each one-on-one match (complexity of N-squared). Approval Voting is simpler still, and is considerably less controversial, in terms of its "failure modes". And if you absolutely must have a run-off method, there's an inverted method of IRV (eliminating the candidate with the most "votes against", rather than the candidate with the fewest "votes for") that's equivalent to Condorcet with cycles resolved by by first-choice count. Rmharman 07:31, 23 April 2006 (UTC)

Both methods fail the participation criterion. It is possible to hurt your favorite by showing up to vote.

[edit] Changes to Example

I'd like to totally change the example in this article. I think it is really complicated and doesn't clarify the simplicity of IRV. I'd like to try something really straight forward instead, like the flash animation | here. Are people supportive of trashing the current example? --Leep4life 20:11, 15 December 2005 (UTC)

I also found the "election for the capital of Tennessee" example a bit confusing when I first read it, although I accepted it as useful for people who are willing to trace through it. The MAIN issue in replacement is that a number of single winner methods use the same example for comparison: Plurality voting system Runoff voting Borda count Approval voting Range voting Ranked Pairs (Others?)

I don't believe in "trashing" too easily the work of others. It may be worthy of trashing perhaps, but hard to evaluate when you can't see the bigger picture and value as a comparative example. I suggest the "responsible" choice is o move ALL of the examples to a new article or set of articles. Then the comparative value will be more apparent.

... I took my own advice and created a combined article including this Tennessee example in all the articles that referenced it.

• SEE NEW ARTICLE: Tennessee voting example

I'll probably get in trouble AGAIN since I GROUPED 9 methods by how people are allowed to vote on a ballot (one vote, ranking, rating). Last time I tried this grouping under voting systems and got in an incomprehensible debate over it, having others deny the existence of explicit "one vote" systems. I surrendered and that's where the illogical "Binary" classification [voting systems are those in which a voter either votes or does not vote for a given candidate] came from Voting_system#Binary_voting_methods. I put Approval in the example article above as a Rating system where it BELONGS, not that I'm looking for a new fight - just can't support foolishness.

!!! INCIDENTALLY !!! current referencing Cumulative voting in Voting_system#Rated_voting_methods is absolutely illogical as well. I'm not touching it, but I'll support anyone who wants to move it to Voting_system#Multiple-winner_methods where it belongs.

I copy&pasted quick short summaries for each method within the combined article, and wrote my own summary as needed. I wanted it very brief, and certainly room for improvement.

I'll let this sit a bit before more action. If this new example article is acceptable, references to this example in each article can be mentioned and link/anchored for each main article.

Tom Ruen 02:31, 17 December 2005 (UTC)

I really like the combination article. It looks really good to have it all together, because then you can easily click to any of the different systems on one page. Can we delete the examples from each of the individual articles now? --Leep4life 06:34, 17 December 2005 (UTC)

Linking to a separate article is not a good idea. A wikipedia article should explain the topic it's on, not require someone to read another article. Worse, the comparative section is in a dangerously perilous place to being just a page for POV advocacy of particular methods, which we absolutely don't need. If we are making comparisons, they must be directly relevant to the article we're discussing and NPOV. An illustrative example at voting system criteria demonstrating what methods pass and fail a particular criteria with the example might be appropriate, however a separate page full of original research is not. Scott Ritchie 07:05, 17 December 2005 (UTC)

Scott, I'm open for suggestions what to do with the content. I sort of think if the content is not appropriate combined, then it's not appropriate divided. I don't have a clear intuitive sense of what is right here. I don't consider made up examples as "Original" research, although this article I wrote DOES qualify much more clearly. IRV - Sample election - favorite season

My judgement is that an example WITHIN a method article ought to illustrate "how it works mechanically" rather than "how it works in regards to voter strategy in nontrivial cases".

In this regard I judge my Season-election example (graphic) alone as the sort of "example" that is valuable. Image:Irvseasoncounting.png I mean the graphic largely alone, not the article. I'm not suggesting this specific graphic be used, ONLY that it represents what I'd be looking for. I want a graphical representation of how IRV can be hand-counted.

SO my vote might be for: (1) Unhappily trash complex example in IRV article(and others?) (2) Substitute a step-wise graphic example that shows how easy it is to count.

Tom Ruen 07:25, 17 December 2005 (UTC)

Why not create an example using markup similar to the one in the tables at Single Transferable Vote? Scott Ritchie 11:01, 17 December 2005 (UTC)

I rewrote the first example into a form which (IMHO) is easier to understand, as well as being a more complete description of the voting process. If you disagree, speak up. Happy-melon 15:25, 21 April 2006 (UTC)

[edit] Removed stuff on STV in Canada

I removed the following, as I don't see how it's relevant to the article on single-winner elections. Perhaps some content should go in History and usage of the Single Transferable Vote or in the relevant articles on the Canadian referendum. Scott Ritchie 09:20, 22 December 2005 (UTC)

I can't speak for the BC-STV paragraph, although I did contribute some of the aftermath stuff; the connection between IRV and BC is 1952 and 1953, and that system's abandomment by undemocratic actions on the part of the Premier it selected.....There should be a history of IRV (by whatever name) in BC here; how it came in, what its effects were, and how it was disappeared....Skookum1 09:38, 22 December 2005 (UTC)

BC used single-winner IRV in 1952 and 1953? Well, that's relevant to some extent (as much as any place using IRV is). However multi-winner IRV isn't particularly relevant for this article, as the BC-STV stuff is. Scott Ritchie 10:59, 23 December 2005 (UTC)

Multi-winner IRV? Did I say that? There was only one winner and on elimination race for each seat, although it's true many ridings were multiple-member ridings (usually double, sometimes triple - but multi-member ridings were split into three ballots so the elimination process could work see e.g. Vancouver-Point Grey and look for the respective years, and then compare the poll results above and below (1949 and 1956). 1952 and '53 in BC were straightforward elimination ballots - lowest total on each count gets taken out, their second-choice ballots applied to remaining, until someone hits 50%. The BC-STV stuff is not relevant to this article to the same degree IMO, since this article is about IRV, not STV. The following passages were apparently excised from the main page, but the basics of them were already in THIS article before I added clarifying details (as the circumstances of the STV idea and the aftermath of the vote were referred to, but not really explained well).

There's a "neutrality dispute" posted on the other page; is the remaining paragraph about '52-'53 under neutrality dispute? Everything there is factual, and I make an effort to not be partisan; the opinion of the electoral fall-out and Bennett's retrenchment after the second election are standards in history of the era, whether by conservative or liberal columnists.Skookum1 06:26, 12 January 2006 (UTC)

[edit] BC-STV Referendum

The British Columbia Citizens Assembly on Electoral Reform met during 2004 and selected STV as the preferred method of voting in British Columbia. This was brought forward in a referendum accompanying the recent provincial election (May 17, 2005), but despite overwhelming support the vote failed the limit required by the legislation mandating the referendum, which had also created the Citizens Assembly, which was three-fifths of the vote, and two-thirds of constituencies. Seventy-seven out of seventy-nine constituencies voted in favour of the proposed BC-STV reforms, but the popular vote missed the 57.69%, missing the required 60% margin margin by a little over two percent. Heavy "no" voting in certain constituences, notably Kamloops where an organized opposition was in place, is credited with tipping the popular vote "against" the proposed system.

[edit] Post-Referendum Debate and Aftermath

In the aftermath, loud opposition from the leader of the New Democratic Party, Carole James, dissuaded Premier Gordon Campbell from following a tide of public opinion and media debate which pointed out that he didn't actually need a mandated vote to implement the new electoral system - he could do it by Order-in-Council in the same way that W.A.C. Bennett had abandoned the elimination ballot after the 1952 and 1953 elections which had brought him to power. The NDP favour Mixed-Member Proportional Representation, which entrenches the role of political parties, as opposed to focussing on preferential order of candidates. Earlier referenda in the province had all been on the 50% plus one basis, and it was widely observed that the figure set to pass the referendum was higher than the popular vote for any government in living memory. Campbell has demurred on the issue, and a new referendum is scheduled during the municipal elections of November 2008 that will essentially be a repeat of the original referendum (although the actual wording of the question is yet to be decided); the main difference is that the Electoral Boundaries Commission will formally set the boundaries of the STV districts that would be used in 2009 if the measure passes and there will be funding for both a 'Yes' and 'No' campaign. Logistical problems faced by Elections British Columbia include preparing different districting plans and voters lists, as well as different organizational machineries required by the different systems. It has not been clear if the referendum to select from the options presented by the legislative committee preparing them will be done by first-past-the-post or elimination ballot. It is generally conceded that any new system will likely result in a handful of seats for the Green Party, and will allow other smaller parties a chance at a seat that was impossible before, except in cases of extreme charisma and popularity by an individual candidate. The NDP's preference for MMP is seen as damage control, the lesser evil of the two main options, the other being BC-STV. Minority governments are expected to be common under any new system, partly because of the fractious nature of BC politics.

[edit] Electoral Reform in Other Provinces

In several other provinces, including Manitoba, Ontario and Nova Scotia, commissions and public hearings on electoral reform have moved steadily in the direction of proportional voting, although some variations of STV and IRV are being examined and may be implemented, with or without referenda depending on the jurisidiction involved and its politics at the time. It is widely believed that the pressure to address proportional representation or preferential voting at the national level will mount once provincial jurisdictions embrace changes to their electoral systems.

[edit] What now?

Well, I've worked through most of this article this evening and changed everything I can think of. What still needs to be done? I suppose We could add some more pictures, but they are unlikely to be of central importance to the topic - they'll be illustrating things like the Fijian parliament building or portraits of the Wade, etc.

Also, does anyone still think the intro is poor? I don't think it needs any more work - I suspect it's been fine for a while, but no-one has thought to change the to-do list!

Happy-melon 20:00, 21 April 2006 (UTC)

---

While the majority of the recent edits have been beneficial, the following additions are (IMO) distinctly not-NPOV, so have been 'clipped'. I suggest that they not be reinserted until they have been made POV-neutral:

"It can therefore be argued that Conderecet takes how much to people dislike a candidate into account as well as how much people like the candidate, while IRV completely ignores how much people dislike the candidate. Therefore, Conderect or Approval systems would produce an elecotorate that is happier with the result."

"Any system that does not increase the amount of voting power because there are more candidates is vulnerable to vote-splitting. IRV does not solve this, it merely transferes the votes of with the same amount of power per a voter, therefore, it will likely lead to two party domination and results rarely different from plurality, just more difficult to compile. Condercet and Approval increase the amount of power per a voter based on the amount of candidates, therefore they are invulnerable to vote-splitting. Borda increases it by too much, therefore it is advantageous to a faction to run as many people as possible."

"Nonetheless, IRV stands out as failing many major criteria that are possible to satisfy simultaneously."

-Happy-melon 17:56, 23 April 2006 (UTC)

[edit] More changes to examples

Happy-melon,

First of all thanks for getting involved in the article (and in Wikipedia if you're new). You wrote:

I rewrote the first example into a form which (IMHO) is easier to understand, as well as being a more complete description of the voting process. If you disagree, speak up.

Clearly the two examples that were there before your changes to Example I were inadequate, but I still don't think we have it quite right so I've now made further changes, by simplifying Example I and completely replacing Example II. I've done this because I think it's best to have a very, very simple first example, followed by a more complicated second example that gives a more complete description. In the process I've done away with the Tennesse example. There have already been concerns expressed about it on this page and I agree with them. Although there are advantages in using a single example across various voting system articles I think the Tennesse example gives an inadequate account of IRV and really seems to have been designed as a way of showing certain differences between IRV and Condorcet more than anything else.

I'd like to keep Example I very simple so that readers can get a quick grasp of the basic principle, as well as because it's reused in the "majoritarianism and consensus" section and that section becomes pretty incomprehensible unless a very simple example is used. However I agree that at least one of the examples needs to be more comprehensive. In particular in the new Example II I've tried to show:

1. What happens when voters with the same first preference have different lower preferences
2. How IRV operates across a few rounds rather than just two
3. The procedure for transfering a vote to the next 'live' preference when other preferences have already been eliminated

However while doing this I've tried to keep Example II relatively simple. In particular to illustrate (1) I don't think it's necessary to have examples of every single possible combination of preferences on a ballot paper. I think one example of split lower preferences is sufficient to explain the process without losing the reader. Another minor alteration is I've changed the format of the tables back to putting the number of voters for each ballot paper at the top rather than the bottom. This is the format used on other preferential system articles and IMHO it's much clearer. Others may disagree though.

Anyway if the two examples in the article still aren't satisfactory lets discuss the matter further.

Iota 18:52, 24 April 2006 (UTC)

[edit] More NPOVing

I've just removed the following text:

IRV also has the problem that it will, undoubtedly, lead to a two-party system. Very rarely are the results changed from the plurality winner (under 5% of the time in Australia), and it is not known how much of this is due to the non-monotonic properties of IRV. Australia's house of representatives, which uses IRV, only has 3 members who are not part of the two-party structure. This is certainly more than the US, which has 1, but definitely not a multi-party system. IRV suffers from the same vote-splitting effects of plurality; they are merely dampened. This is because IRV does not solve the main problem that causes vote-splitting and the two-party system under plurality: the voter has 1 vote for 2 candidates, and the same amount of power to decide between 10. IRV merely transfers this vote, and it is still very, very simialar to the plurality system in affect. Obviously this is going to lead to strategic two-party voting.

This was in the wrong section, is not NPOV, and, in fact, just reproduces information already given in various parts of the article. The essential point, that in Australia IRV produces a two party system very similar to plurality, I've added to the "effect on parties and candidates section". The claim that the results differ by "under 5%" is interesting. Can anyone provide a source though?

Iota 01:47, 27 April 2006 (UTC)

---

Well done on finding the how-to-vote card, Iota, and some great contributions. I prefer the new examples both to the originals and to my modifications. Nice job!

[edit] Singular they

Those editors who seem to really care what we use for pronouns should check the Wikipedia article on Singular they. Since we are an encyclopedia, we should try to use what is accepted as formal grammar for written usage, and not informal speech. At any rate, note that according to that article the usage of "their" when a person is of indeterminate gender seems to be the least preferred usage of all.

There is also a meta on the whole topic that may or may not interest you.

One more note would be that in the context it is used in this article, either gender specific pronoun would be acceptable, since it is an example. What I've seen to be more common than using "singular they", is to randomly choose a gender specific pronoun and use it in a generic way. Peyna 23:46, 17 May 2006 (UTC)

Thanks for bringing those links to our attention, Peyna. I am not particularly bothered between "her", "his" or "their", but I intensely dislike the use of "his or her". While I'm not calling a formal vote, I encourage other editors to make their views known. While I am, as I say, more in favour of one of the gender-specific pronouns, I feel that the most important thing is to be consistent.

Consider also that in the equivalent section of single transferable vote (a featured article which has been listed on the main page), the pronoun "her" is used. Happy-melon 19:41, 19 May 2006 (UTC)

[edit] Corporate Governance & Civil Society

If there are any examples of Instant runoff voting systems from the corporate world then it would be great to see them included. For instance in the election of company board members. Also examples from civil society (eg trade unions, positions in religious bodies etc) would be of interest. Terjepetersen 13:19, 5 October 2006 (UTC)

[edit] elimination in IRV

I see from reading this article that the candidate with the lowest first preference votes is eliminated immediately, not given the chance to gather second and third preference votes.

What is a system where no-one is eliminated, and keep gathering votes until someone has an overall majority? So that in example 1, Brian would collect the 42 second preference votes from Catherine and 39 from Andrew? BillMasen 18:30, 8 October 2006 (UTC)

——

I think what you're asking for makes some sense -- Bob, Carol, Ted & Alice all run and Ted has a majority of second choice votes but is the lowest first choice vote getter. The problem is, everyone's already decided that Ted isn't their highest preference and it seems unfair to the voters who picked other candidates with higher prefernces to make them "throw away" their higher preference choices and make them accept their lower choices as their first preference. Plus, I think instant runoff is about allowing people to take a risk on third party candidates without feeling like they're throwing away their votes.

________________

I don't exactly mean them throwing away their first preference choices. I mean that if a candidate fails to get a majority of first preference votes, every candidate gets the first pref PLUS their second pref votes, and then third pref and so on until someone has a majority.

Is this a voting system which exists?

BillMasen 15:32, 14 October 2006 (UTC)

BillMasen: I believe you're describing Bucklin voting. Rmharman 18:55, 8 January 2007 (UTC)

[edit] blog references?

Hmmmmm... I'm curious by the inclusion of a blog entry in the references. If random blogs are "sources", I'm sure you can find ennumerable such sources. How does Wikipedia judge validity of such web sources?

It would seem to me that if something would be considered original research to be included in Wikipedia, then linking to a blog or individual website ought to fit in the same category. So the only reason for linking to an external source is if it is a web copy of a published resource (or if it is a summary of such a resource).

Thoughts anyone? I accept it is nearly hopeless, except brutally stripping out probably 90% of the external links found. Tom Ruen 04:15, 6 November 2006 (UTC)

[edit] Practical implications

The following quote is in this section:

"If counting takes place in several places for a single IRV election (as in Australia), these counting centres must be connected by a securely authenticated channel (historically, in Australia, the telegraph was used) to inform them which candidate has come last and should be dropped."

This isn't how the count works in practice in Australia. The final count (including the official preference flows) for each electorate is done in one place a few days after election night when all the absentee and postal votes have had a chance to arrive. On election night, individual counts are conducted in each polling place with a first-preference count done first, followed by a two-candidate-preferred count, where each polling place distributes preferences to the two candidates the divisional returning officer determines will be the likely two final candidates. If these aren't the two final candidates, it just means the figures on the night for that electorate are a bit dodgy and they will be rectified over the following days. But there is no liaison between counting centres in Australia on election night to determine which candidates are to be excluded. Crico 01:45, 14 November 2006 (UTC)

See p17-18 of the AEC's Scrutineer's handbook for an official description of what I was just talking about Crico 02:06, 14 November 2006 (UTC)

[edit] strike approval plug

I took out thes sentences under (Practical implications)

For these reasons some electoral reformers argue that it is simpler to change from plurality to approval voting than to a preferential system, although that theory has not been borne out in practice: instant runoff voting has been far more successful at winning adoptions both in public elections in American states and cities and in student eledctions at universities.

I judged this as a biased statement intended to promote approval rather than to explain IRV. Tom Ruen 05:17, 14 November 2006 (UTC)

I pulled this too, seemed irrelevent since we're already talking about counting by computer! Tom Ruen

For example the more sophisticated versions of Condorcet's method are practical for large elections only if counting is done by computer.

[edit] undocumented paragraph removed here

Another alternative that has been called "Progressive Advancement" is for the candidate with the most first preferences to advance to the next round of voting. The ballots are then recounted and the next remaining candidate with the most first preferences advances to the next round of voting. This process continues until all candidates but one have advanced to the next round, at which point the last unadvanced candidate is eliminated. The counting then resumes to determine if there is a winner based on a majority of first preferences. If not, another round of progressive advancement occurs until either a winner is found, or until all candidates except one have been eliminated. ^{[citation needed]}

Tom Ruen 23:13, 16 November 2006 (UTC)

[edit] Removed text restored here

I should have been more careful before I started, but an anonymous user (139.62.107.233)[1] took out four significant sections completely, so I went back and pasted the below, if anyone wants to decide what to do. Tom Ruen 05:45, 14 November 2006 (UTC)

[edit] Similar systems

[edit] Runoff-voting

The term instant-runoff voting is derived from the name of a simpler class of voting systems called runoff voting. In runoff voting voters do not rank candidates in order of preference on a single ballot. Instead a similar effect is achieved by using multiple rounds of voting, often held on different days. The simplest form of runoff voting is the two-round system, where voters vote for only one candidate but, if no candidate receives an overall majority of votes, another round of voting is held from which all but the two candidates with most votes are excluded.

Runoff voting differs from IRV in a number of ways. The two-round system can produce different results due to the fact that it uses a different rule for eliminations, excluding all but two candidates after just one round, rather than gradually eliminating candidates over a series of rounds. However all forms of runoff voting differ from IRV in that voters can change their preferences as they go along, using the results of each round to influence their decision. This is not possible in IRV, as participants vote only once, and this prohibits certain forms of tactical voting that can be prevalent in 'standard' runoff voting.

A closer system to IRV is the exhaustive ballot. In this system only one candidate is eliminated after each round, and many rounds of voting are used, rather than just two. Because holding many rounds of voting on separate days is generally expensive, the exhaustive ballot is not used for large-scale public elections. Instant-runoff voting is so named because it achieves a similar effect to runoff voting but it is necessary for voters to vote only once. The result can be found 'instantly' rather than after several separate votes.

[edit] Contingent vote

The contingent vote is the same as IRV except that all but the two candidates with most votes are eliminated after the first round; the count therefore has only two rounds. This differs from the 'two round' runoff voting system described above in that only one ballot is conducted. The two rounds therefore both take place after voting has finished. Two particular variants of the contingent vote differ from IRV in a further way. Under the forms of the contingent vote used in England and Sri Lanka voters are not permitted to rank all of the candidates, but only a maximum number. Under the variant used in England, called the supplementary vote, voters are permitted to express only a first and a second preference. Under the Sri Lankan form of the contingent vote voters are permitted to rank only three candidates. The supplementary vote is used for mayoral elections, while the Sri Lankan contingent vote is used to elect the President.

While superficially similar to IRV, these systems can produce different results. If, as can occur under all forms of the contingent vote, more than one candidate is excluded after the first count, a candidate might be eliminated who under IRV would have gone on to win the election. If voters are restricted to a maximum number of preferences then it is easier for their vote to become exhausted. This encourages voters to vote tactically, by giving at least one of their limited preferences to a candidate who is likely to win.

[edit] Tactical voting and strategic nomination

Main article: Tactical manipulation of instant-runoff voting

Instant-runoff voting is intended to reduce the potential for tactical voting by eliminating 'wasted' votes. Under the plurality (or first past the post) system voters are encouraged to vote tactically by voting for only one of the two leading candidates, because a vote for any other candidate is unlikely to affect the result. Under IRV this tactic, known as 'compromising', is sometimes unnecessary because, even if the voter's first choice is unlikely to be elected, her vote has the opportunity of being transferred to her second or subsequent choices, who may be more successful. However the tactic of compromising can still be used in IRV elections, as can another tactic called 'push over'. IRV is immune to 'burying', which is possible under some other preferential systems.

IRV election can also be influenced by strategic nomination; this is where candidates and political factions attempt to influence the result of an election by either nominating extra candidates or withdrawing a candidate who would otherwise have stood. IRV is vulnerable to strategic nomination for the same reasons that it is open to the voting tactic of 'compromising'. This is because a candidate who knows they are unlikely to win can bring about the election of a more desirable compromise candidate by withdrawing from the race, or by not standing in the first place. By withdrawing candidates a political faction can avoid the 'spoiler effect', whereby a new candidate 'splits the vote' of its supporters. However, the spoiler effect is less of a problem in IRV than under the plurality system because there are opportunities for 'split votes' to be concentrated on one of the candidates as the rounds progress, whereas under the plurality system votes cast for a losing candidate are simply lost.

[edit] Effect on parties and candidates

Like other preferential voting systems, IRV encourages candidates to appeal to a broad cross-section of voters in order to garner lower preferences. However this characteristic may be diminished by the fact that lower preferences have less influence on the final result under IRV than under some other preferential systems.

IRV is an election method designed for single-seat constituencies. Therefore, like other single-seat methods, if used to elect a council or legislature it will not produce proportional representation (PR). This means that it is likely to lead to the representation of a small number of larger parties in an assembly, rather than a proliferation of small parties. Under a parliamentary system it is more likely to produce single-party governments than PR systems, which tend to produce coalition governments. While IRV is designed to ensure that each candidate elected is supported by a majority of those in her constituency, if used to elect an assembly it does not ensure this result on a national level. As in other non-PR systems the party or coalition which wins a majority of seats will often not have the support of an overall majority of voters across the nation. IRV is also one of many voting systems that is subject to vote-splitting, which almost always results in a two-party structure. In Australia, the only nation besides Fiji to use IRV for the election of legislative bodies, IRV produces results very similar to those produced by the plurality system. This has resulted in a two party system similar to those found in many countries that use plurality. If the first preferences of Australian voters were counted on a First Past the Post basis, their elections would produce the same victors about 94% of the time^[1].

Where preferential voting is used for the election of an assembly or council, parties and candidates often advise their supporters on how to use their lower preferences. As noted above, in Australia parties even issue 'how-to-vote' cards to the electorate before polling day. These kinds of recommendations can increase the influence of party leaderships and lead to a form of pre-election bargaining, in which smaller parties bid to have key planks of their platforms included in those of the major parties by means of 'preference deals'.

[edit] Condorcet vs. IRV

The following sentence (from Majoritarianism and Consensus) doesn't make much sense:

"In fact, when IRV elects a candidate other than the Condorcet winner it will always be that the majority of voters prefer the Condorcet winner to the IRV winner (the only system that always elects the Condorcet winner is Condorcet's method)."

First of all, the main part of the sentence seems to be a tautology with no information about IRV, since by definition, the Condorcet winner is preferred by a majority of voters over any given opponent. In other words, the sentence would be true if IRV was replaced with anything.

Second of all, there is no method called "Condorcet's method". Any method satisfying the condorcet criterion is a Condorcet method, but there are several different ones, so it doesn't make sense to say that only Condorcet's method always elects the Condorcet winner (since this implies that there is only one voting system that elects the Condorcet winner). —The preceding unsigned comment was added by 12.72.242.244 (talk) 00:15, 7 December 2006 (UTC).

"This might suggest that Andrew has the enthusiastic support of a large portion of the electorate (if not a majority), while Brian is an uninspiring compromise." - this sentence is extremely biased. If the majority of the population were enthusiastically supporting a candidate, they would have marked that candidate. Also, whether or not the candidate is "uninspiring" is completely a matter of opinion. The Condorcet winner in this example may very well have been more "inspiring", the other man could've simply been Hitler. Condorcet produces the comprimise while IRV produced the plurality, as no true majority could be arrived at for obvious reasons. I have attempted on numerous occassions to replace it with the more reasonable and unbiased "This might suggest that Andrew has the enthusiastic support of a large portion of the electorate, while Brian was more of a comprimse candidate". Is there any reason to object to this, and why do you continually re-bias the page?

[edit] Problems

A couple of issues with this article.

1. There is frequent mention of something called "runoff voting", but there is neither an explanation of what it is nor a link to a page that explains it.
2. The example section refers to a previous example that doesn't exist

Hope this helps. JulesH 19:34, 7 January 2007 (UTC)

I linked refernces to Two-round system. Tom Ruen 22:10, 7 January 2007 (UTC)

I agree the example back references makes no sense. Article history needs looking into to sort it out. Tom Ruen 22:13, 7 January 2007 (UTC)

[edit] Tie breaking rule

I removed this by an anonymous edit:

Eliminating all other candidates and seeing who would win in a pairwise comparisson, and the candidate that loses the pairwise comparrison is eliminated.

Bad spelling, and unclear procedure but seems to imply a Condorect-style elimination on the bottom which would be unacceptable in IRV with keeping only one active vote at a time. Tom Ruen 23:38, 23 January 2007 (UTC)

[edit] This page is now protected

This page is hereby protected due to edit warring. Please discuss the problem in the below section and contact me here when the issue is resolved. --Deskana (talk) (review me please) 23:33, 9 March 2007 (UTC)

[edit] Discussion